Neuroinflammatory responses may be dependent on the initiation of innate immune responses triggered by the stimulation of intrinsic brain cells by pathogen-associated molecular patterns (PAMPs), repeated structural motifs generated by microbes that are not normally found in the host or by debris from apoptotic or necrotic cells following injury. However, there is a lack of basic understanding of which cell types in the brain respond to stimulation of PRRs, as well as the pathways of neuroinflammation, neuroprotection and/or neuronal damage induced when these PRRs are activated on different cell types. Understanding the mechanism of PRR-induced activation of different cell types in the CNS is important for understanding viral pathogenesis as well as identifying potential pathways for therapeutic treatments. Our laboratory has focused on understanding the response of intrinsic brain cells following PRR activation or during virus infection and determining the downstream effects of innate immune activation on neuroinflammation and neuropathogenesis. In FY2012, we analyzed the neuroinflammatory response to TLR7 and TLR9 in the developing brain and identified differences in cell types in mediating the neuroinflammatory response. We are currently examining the role of these TLRs as well as other PRR in mediating the innate immune response during virus infection in the CNS.